Weight colors not affecting strength of bones!
Weight painting (or assigning) makes comparison between at least two assignement, with an automatic normalization of values:
take two vertices (let we call them A and B) and two bones (boneC and boneD):

if you assign to the boneC vertex group a weight for A 1.0 and for B 0.5, and to the boneD vertex group no weights, then you move the boneC in pose mode, A and B will move exactly with it.

In the same situation let's now assign a weight of 1.0 for both A and B to the boneD vertex group: now move the bone C, 4 BlenderUnits toward left: A will move 2 BU left, while B will move 1.33333 BU only.

Consider that, in case of single wieght assignement, even a value of 0.0001 is infinitely greater than 0.0, so it will be treated in the same way as a 1.0 assignement.